How about this set:
Pursuit-STAB; the rest of this moveset is built around forcing switches, giving this more power.
Thunder wave/toxic/Protect-Thunder wave cripples, and toxic damages, works well with Mischievous. Protect works well with torment/encore if you need to stall them out.
Torment- works well since nobody is going to use other moves, they'll just finish this thing off. Torment prevents double attacks, great for choice users, which are fairly popular in lower tiers.
encore/Taunt-Taunt prevents status moves from being used, and encore can be combined with torment to trip up the opponent pretty well.
Why does this thing have nasty plot!? but no good moves to use it for, except shadow ball!